Hi Randy;

I can't say categorically that this is the best way to fill cracks, but so far, it has worked the best for me. I use homemade wood flour, obtained while sanding the various woods that make up my kayak. It is not sawdust, but much finer, looks & feels like bread flour. You could quickly make some with a few small representative scrap strips and a power sander of some sort.

I mix LOTS of wood flour with plain old Elmer's carpenter's glue - It is mostly wood flour, you'd be surprised how far a little glue will go. I use this thick paste, sometimes adding colloidal silica to lighten the color and smooth it. I have found it retains the color of the wood best, sands easliy, and is quick to prepare. I force it into any seams with a small wooden stick, from my collection of popsicle sticks . . . 8-)

My deck and hull currently have glue lines filled with (1) glue, (2) epoxy and wood flour, (3) vinyl patching compount colored with wood flour and/or water based pigment, and (4) glue and wood flour. Frankly, I can plainly see all except for the last, which have flat disappeared into the surface, even when wet. Fortunately, I make pretty tight seams or I might be disappointed by my tests using the first 3 techniques.

I hope this helps, but I'd recommend tests on the hull before deciding what you will use - I am by no means an expert in this area.

Best Regards, Spidey